Conventionally, a digitized input device such as an image scanner, digital camera, facsimile receiver, or image file system (reading section) is generally connected to a computer and executes input processing under the control of the computer. That is, the input device plays a passive role that data is extracted by the connected computer. In recent years, push-type input devices have also been developed, in which the input device side actively executes the input processing and sends data to a data sending destination.
Conventionally, a digitized output device such as a printer, facsimile transmitter, or image file system (writing section) is generally connected to a computer and executes output processing under the control of the computer. That is, the output device plays a passive role that data is sent from the connected computer. In recent years, pull-type output devices have also been developed, in which the output device side actively reads out data from a data sending source and executes the output processing.
A scheme of building a multi-functional system is known, in which an input device and an output device are connected directly (i.e., without intervening any computer serving as a control entity and data mediator), and the functions of the devices are combined, thereby providing a composite function. In such a multi-functional system, the input and output devices can be connected only when the interface condition of the input device matches that of the output device, including the protocol and input/output speed, control system, transferable data format, and image resolution. For this reason, input and output devices can be directly connected in only a fixed combination where the interface conditions are designed in advance to match each other. As such a multi-functional system, for example, a digital copying machine which connects a push-type image scanner to a plurality of passive printers through cables in advance has been developed. This system can implement, e.g., multiple copy for obtaining copy outputs in number equal to the number of printers by one scanning cycle for an original page. Such a system in which a single input device and a plurality of output devices are permanently combined has been developed.
The network technology represented by the Ethernet recently exhibits remarkable progress and expansion. Not only a number of input and output devices are connected to a single LAN but also Internet connection between a plurality of LANs makes it possible to combine an input device connected to a LAN with an output device connected to another LAN. Additionally, the configuration is often usually modified by adding or removing an input or output device to or from a network. Hence, an enormous number of input and output devices, which are reachable through a network, i.e., which are combinable in principle, form combinations dynamically, so a demand has arisen for a method of building not only a system with a fixed combination but also a combination-type multi-functional system flexibly using a set of combinable input and output devices at a time. To meet this requirement, a multi-functional system has also been developed, in which a combination of connectable input and output devices is found by negotiation between the input and output devices for the interface condition, i.e., the combination is variable.
Another system has been developed, in which when the input and/or output device supports a plurality of interface conditions, the input and output devices negotiate in advance to determine interface conditions under which the devices can be connected, and the input and output devices are connected under the respective interface conditions. The present inventors have previously proposed a method of building a virtual input/output device (system) based on a transfer path profile. According to this method, information (to be referred to as a device profile) representing the characteristics of each device connected to a network is managed by a database. In addition, transfer path information for a combination of combinable input and output devices which are selected on the basis of the device profiles and transfer condition information related to transfer (these pieces of information will be referred to as a transfer path profile) are also managed by the database. The user accesses the database from the operation panel of an input or output device and selects a transfer path profile, a composite function formed from a complex combination of input and output devices can be designated and used by a simple user interface. Furthermore, the input/output device group that forms the transfer path can be controlled on the basis of the transfer path profile.
In the above-described method of building a combination-type multi-functional system using a “transfer path profile”, the input and output devices can be flexibly and dynamically combined. However, the combinations of combinable devices are limited to a combination of an active input device and a passive output device and a combinations of a passive input device and an active output device. More specifically, in attempting to combine, e.g., a push-type scanner with a pull-type printer, these devices cannot be actually combined because both the devices are designed to actively start data transfer, and the transfer control directions do not match.
Conversely, in attempting to combine a conventional passive scanner with a passive printer, these devices cannot be actually combined because both the devices are designed to wait for a transfer instruction from the other party of data transfer, and the transfer control directions do not match.
For this reason, even when a number of input and output devices are connected to a reachable network, the number of combinations available as transfer path profiles may be substantially small depending on the transfer control directions of the input and output devices. That is, many kinds of input and output devices connected to the network cannot be effectively put into a transfer path profile because of mismatching in assumed transfer control direction.
In the conventional method of building a combination-type multi-functional system using a transfer path profile, input and output devices can be flexibly and dynamically combined. However, only a combination of input and output devices whose processible transfer data formats completely match can be included in the transfer path profile. More specifically, a virtual input/output device can be constituted only when the transfer data expression format such as an image format or resolution for image data transfer or, e.g., a page description language (PDL) for page description data transfer matches between the input and output devices. For this reason, even when a number of input and output devices are connected to a network, the number of combinations available as transfer path profiles may be substantially small depending on the data format processed by the input and output devices. That is, many kinds of input and output devices connected to the network cannot be effectively put into a transfer path profile because of mismatching in processible transfer data expression format.
In the prior art, input and output devices can be flexibly and dynamically combined. However, to implement a virtual input/output device formed from a combination of one input device and a plurality of output devices, processing that must be executed by the input device is complex because the input device side takes the responsibility of data transfer processing for each of the plurality of output devices. Hence, the input device must have a control procedure for data transfer to a plurality of output devices in advance even when the input device is used to simply create input data and transfer the data to a single destination. This generates stricter requirements for resources necessary to constitute the device, i.e., resources such as the CPU performance, memory capacity, and network interface performance, resulting in an increase in cost of the output device.